Troubleshooting Trailer Wiring Harness that Lights Up Tow Vehicle Taillights When Connected

Question:

2011 Honda Odyssey T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector #118521 I installed the above wiring harness on my 2011 Odyssey about 3 years ago and it has worked perfect up until today. When I connected the trailer lights up today the trailer running lights all came on with no lights on the van and the van not running. Turned on the van and then the van lights and all lights worked as they should. Turned off the lights and the van and the trailer running lights stayed on. Not sure what is happening, but wondered if the black box power module in the T-One wiring harness could have become defective? Have there been any other occurances like this? Or is there something else that I missed? Thanks for your advise

asked by: Steve

Helpful Expert Reply:

What you described sounds exactly like a shorted out converter box for the part # 118521. You will need to replace the converter, but before you do that you will want to check the wiring of the trailer for shorts as that is what most likely caused the box to short out.

When a trailer sits for an extended period of time (typically in winter), corrosion on the trailer connector has a more likely chance of showing up which can cause shorts.

I would not recommend reconnecting you trailer to your vehicle until you have found and fixed the short and then replaced the converter.

expert reply by: Jameson C